Waste disposal apparatus

ABSTRACT

An apparatus is provided, wherein waste solids are prepared for disposal. The solids are wet pulped into a slurry form, having some solid material therein, with the solids then passing into a trap, whereby larger solid particles that have not been sufficiently reduced in size in the pulper may be collected at the bottom, for carriage by an ejector toward which the particles may optionally receive assistance from a water line, to discharge receptacle. The slurry passes from the trap into another apparatus which further comminutes solids carried by the slurry, for delivery to a press, whereby water is extracted therefrom, with the water then being recycled to the pulper, and with the compacted solids from the press being discharged into the discharge receptacle. A vent is provided, at the outlet of the trap.

United States Patent 91 Craig et al.

[54] WASTE DISPOSAL APPARATUS Filed:

Inventors: Sam N. Craig, Devon; Ellis R.

Warner, Jr., West Chester; Wayne T. Buckman, Pipersville, all of Pa.

U.S. Cl. ..24l/43, 24l/46.l7, 241/78,

Int. Cl. ..B02c 18/40 Field of Search ..241/43, 45, 46.17, 68, 76,

References Cited UNITED STATES PATENTS Combs et a1 ..241/43 Baxter, Jr.....24l/46.17 X Carlson ..24 1/ 68 Fukuda ..241/l01 X Feb. 13, 1973 [57] ABSTRACT An apparatus is provided, wherein waste solids are preparedfor disposal. The solids are wet pulped into a slurry form, having somesolid material therein, with the solids then passing into a trap,whereby larger solid particles that have not been sufficiently reducedin size in the pulper may be collected at the bottom, for carriage by anejector toward which the particles may optionally receive assistancefrom a water line, to discharge receptacle. The slurry passes from thetrap into another apparatus which further comminutes solids carried bythe slurry, for delivery to a press, whereby water is extractedtherefrom, with the water then being recycled to the pulper, and withthe compacted solids from the press being discharged into the dischargereceptacle. A vent is provided, at the outlet of the trap.

6 Claims, 3 Drawing Figures mnminremmm A 3,716,197

sHm 10F 2 INVENTORS SAM N. CRAIG ELLIS R. WARNER BY WAYNE T. BUCKMANWWW/ ATTORNEYS WASTE DISPOSAL APPARATUS BACKGROUND OF THE INVENTIONVarious techniques have been developed in the past, directed towardcomminution of waste material, into a size that will enable the materialto be carried away via sewage pipe lines, and the like. In otherinstances, the waste has been reduced in size, to enable handling of thesame by conventional techniques, such as by trucking the waste to adisposal site.

In either type of system, as well as in other types of systems, itbecomes desirable to shred an aggregate mixture of waste, such ascardboard, paper, rags, plastics, glass containers, metal cans and thelike. By shredding such material, and optionally grinding the samethereafter, this waste is substantially reduced in volume, and maythereafter be handled by conventional techniques, with great facility.

Most particularly, in comminution techniques, wherein a pulper of thetype that abrades the waste v material in a liquid medium, forshredding, cutting and tearing the same, whereby particles are entrainedand otherwise conveyed in a liquid medium after they have been reducedin size, various techniques have been employed. One novel technique isto deliver such pulped slurry either directly to a press, or.preferablypassing through another comminution stage, most preferably of the typewherein a positive shearing or like cutting action is effected onparticles carried in the slurry.

In many systems, it becomes desirable to minimize the time in which agiven portion of the slurry remains within a given apparatus. Thus, forexample, in the use of a pulping apparatus that performs abrading uponsolid debris in a liquid medium, if a screen size at the bottom of thepulping apparatus has sufficiently small passageways, and if the debrisis pulped within the pulper for a sufficiently long period of time,virtually all of the material being pulped will be reduced to a sizesufficient to be pressed. However, if it is acceptable that thedischarge from the pulping apparatus would contain a small percentage ofmaterial that has not been comminuted to the desired pre-selected size,the length of time for any give batch of waste material to remain in thepulper is enormously reduced. Thus, if the discharge from the pulper cancontain an acceptable percentage of substantially unpulped orinsufficiently pulped solids, the pulping apparatus then achieves agreatly increased capacity for handling material. In accordance with thepresent invention, an apparatus is utilized at the discharge end of thepulper, in order. to permit an increase in the capacity of the pulper,in such a manner as to obviate the problems 7 discussed above.

SUMMARY OF THE INVENTION The present invention is directed towardproviding, downstream of a pulping tank, a trap tank or hopper, wherebythe discharge from the pulping apparatus contains some undesirably sizedparticles, generally glass, steel and the like, whereby the trapreceives the discharge from the pulping apparatus, forlater delivery toa selected subsequent piece of apparatus, but wherein these undesirablysized solids accumulate in the trap and are discharged from the bottomthereof, to an ejector which physically removes such solids from theslurry. The slurry with the solids removed therefrom then leaves thetrap, and continues optionally onto another comminution station, or to apress, through both in serial fashion, or into sewer discharge, asdesired.

Accordingly, it is a primary object of this invention to provide a trapapparatus that is adapted to be used with a pulping tank, for increasingthe handling capacity of the pulper.

It is a further object of this invention to provide a novel trap forcollecting solids from a slurry or like liquid medium, with an ejectorfor lifting solids from the liquid medium.

It is another object of this invention to provide a novel two-stagegrinding or comminution apparatus, utilizing a trap with a solidsejector therefor.

It is a further object of this invention to provide a novel completesystem, including a pulper, another comminution apparatus downstream ofthe pulper, a trap disposed between the pulper and other comminutionapparatus, with an ejector for removing solids from the trap, with apress disposed operationally downstream of the other comminutionapparatus, with suitable vent and water return lines, and with solidsfrom the ejector and press being adapted to be emptied into areceptacle.

It is another object of this invention to provide a novel combination ofa pulper and a trap, with an ejector associated with the bottom of thetrap for extracting solids collected from a slurry that is dischargedfrom the pulper, along with a novel vent arrangement from the outlet ofthe trap.

Other objects and advantages of the present invention will be readilyapparent to those skilled in the art from a reading of the followingbrief description of the drawing figures, detailed description of thepreferred embodiment, and the appended claims.

IN THE DRAWINGS FIG. 1 is a front elevational view, partiallyschematically illustrated, of a complete system in accordance with thisinvention, with portions of the various apparatus being illustrated insection, for the sake of clarity.

FIG. 2 is a transverse sectional view, taken along the line Il-II ofFIG. I, and wherein the means for discharging solids from the hopperbottom of the trap is illustrated, along with means for ejecting thesolids thus discharged into a receptacle.

FIG. 3 is a fragmentary transverse sectional view, similar to a portionof FIG. 3, but wherein an optional alternative bottom of the trap forsolids ejecting is illustrated.

Referring now to the drawings in detail, reference is first made to FIG.1, wherein there is illustrated a complete system in accordance withthis invention, generally designated by the numeral 10.

The system 10 includes a pulping device 11, of the type which is adaptedto pulp assorted debris therein, in a liquid medium. The pulpingapparatus 11 is constructed generally along the lines of the pulpingapparatus disclosed in U. S. Pat. No. 3,489,356, and has a top (notshown) that is adapted to be opened and receive a batch of assortedtrash and the like therein. A fresh water supply 12 is provided to thepulping apparatus l I. An impeller plate 13 is disposed at the bottom ofthe apparatus 11, driven from a shaft 14 that in turn is driven by asuited pulley belt or like arrangement 15, with the impeller plate 13having a plurality of abrading teeth 16 or the like for abrading,comminuting, shearing and the like of trash particles contained in thebottom of the apparatus 11, in a liquid medium 17 provided by water fromthe inlet 12. The particles thus achieve a desired size that ispre-selected in accordance with openings in a screen 18, and passthrough such openings 20, into an evacuation chamber 21. It will benoted that the size of the openings 20 is selected in accordance withthe desired capacity of the pulping apparatus 11, such that, as desiredfor the reasons set forth above, some solid particles may be passed intothe discharge chamber 21, of the pulping tank 11. Thus, the dischargefrom the pulping tank 11 passes into a trap 22, carrying someundesirably sized particles. Once such undesirably sized solidparticles, such as metal fragments, glass and the like enter the trap22, they will tend to settle in the bottom of the trap 22, because therate of flow of liquid through the trap 22 is substantially less thanthe rate of flow of that liquid through the discharge chamber 21,because of the increased size or sump-like effect attributed to the trap22.

The liquid slurry in the trap 22, with the undesirably sized solidparticles settled out therefrom, then leaves the trap, and passes,through a discharge line 23, into a second stage comminution apparatus24. The apparatus 24 is adapted to positively grind any very small metalparticles, such as hospital hyperdermic needles and the like, byengaging them between teeth on a rotating plate 25 and a toothedperiphery 26 thereof, while also additionally abrading and severingfibers and other particles carried in the liquid medium of the pulpedslurry, with such slurry also being pumped through the discharge line 27to a press 28. The secondary comminution apparatus, as has beenmentioned above, is of the positive grinding type, for physicallyengaging particles between the toothed periphery 26 and the plate teeth25, in distinction to being a comminution apparatus of the pulping type,which continuously shreads or abrades particles carried past teeth 16thereof in a liquid medium. Thus, the comminution apparatus 24 is of thetype disclosed in application Ser. No. 730,331, filed May 20th, 1968,now U.S. Pat. No. 3,565,350. This second stage comminution apparatus 24is driven by a suitable pulley belt arrangement 30 or the like, asdesired.

The slurry, once entering the press 28 is compacted, with carried solidparticles being substantially separated from the liquid medium,generally by means of single or double screw conveyors that squeeze thewater from the solid particles in the press 28, with the water beingdrained through a suitable screen arrangement or the like, and with thesolids being delivered upwardly, for discharge from the press 28 througha chute 31, into a waste receptacle 32.

It will be noted that the press 28 may preferably be of the general typedisclosed in U. S. Pat. No. 3,426,677.

Water that is squeezed from the solid particles in the press 28 isdelivered from the press 28 through a line 33, back into the pulpingapparatus 1 1, for re-use as the carrying liquid medium.

It will further be noted that, in lieu of discharging from the trap 22,through the line 23, it may be desirable to discharge the liquid mediumfrom the trap 22, directly to a press 28, depending upon whether or notthe system is handling components such as hospital needles and the likerequiring another stage of comminution. Also, if the waste included inthe slurry that is being discharged through the line 23 from the trap 22is desirably sized, the line 23 may be connected directly to a sewer, asanother option.

It has been found desirable to place a vent line 34, as illustrated inFIG. 1, from the discharge line of the trap 22, for discharging gasesand other substances back into the pulping apparatus 11, as illustrated.As has been mentioned above, the liquid in the trap 22 has asubstantially reduced flow, due to the volume of the trap 22, and theability of the trap 22 to act as a sump. Thus, rather than venting fromthe trap 22, which may perhaps lend itself to accumulation of some verylight substances such as polystyrene and the like in the vent line, orelse tend to clog the vent line, it has been found to be desirable toplace the vent line 34 at the discharge of the trap 22, for venting at alocation of increased flow of the liquid medium. By thus placing thevent line 34, some very light substances such as polystyrene foam willbe carried past the opening 35 in the screen 36 at the inlet of the ventline 34, in a sufficiently rapid manner that they will not tend toaccumulate across the opening 35 of the screen 36, whereby the vent line34 will not become clogged, and such polystyrene foams and the like willbe further comminuted within the apparatus 24. Thus, it will be clearthat this placing of the vent line 34 will permit discharge of gases andemulsions and foams formed within the pulping apparatus and trap 22, todischarge through the openings 35, into the vent line 34, and back intothe pulping apparatus 11. Such foamsthat are desired to be re-cycledback through the vent line 34 are those bubbly type of foam emulsionsthat are formed by the chemical and mechanical abrasion of fineparticles in a liquid medi- With particular reference to FIG. 2, it willbe seen that the trap 22 is adapted to be maintained substantially full,if desired, in receiving a slurry through the opening 40 from thepulping apparatus discharge chamber 21. The trap 20 has a top cover 41,to prevent splashing of a slurry therefrom when the same is full. Itwill be noted that the bottom walls 42 through 45 of the trap 22 aresloped inwardly for conversions at an outlet 46. Thus, heavier solidtrash and debris particles will tend to settle outwardly through thetrap outlet opening 46, through the S-shaped discharge line 47, and bedelivered into an ejector 48.- The ejector 48 is adapted to contain asubstantial volume of liquid medium, generally approximately of the samelevel as liquid medium within the hopper 22. The ejector 48 willgenerally include a conveyor 50 for example, of the chain type asillustrated, whereby chains 50 are carried on spaced sprockets 51 and 52at, respectively, lower and upper ends of the ejector 48, with onesprocket such as that 52 being suitably driven by a motor and beltarrangement 54, such as that illustrated in FIG. 2. The chains 50 carrya plurality of identical bins 55, having bottoms 56 of screen wire orthe like, which are adapted to scoop up solid debris gathering in thebottom 57 of the ejector 48, and to lift the same upwardly, asillustrated by those bins 55 at the left side of the ejector 48 in FIG.2, until such bins 55 are above the liquid level within the ejector 48.As the bins 55 then round the upper end of the ejector 48 in thevicinity of the upper sprockets 52, the bins 55, from which the liquidhas already been strained through the screen bottoms 56 thereof aftersuch bins 55 have passed above the level of liquid in the ejector 48,then pass around the upper end of the sprockets 52, and become inverted,for easy discharge of solid material therefrom, downwardly through ahopper 58 thereof, into the receptacle 32.

The line 33 between the press 28 and the pulper 1 l is provided with aT" 60, to which is connected a water return line 61 from the press 28,with the lines 33 and 61 having suitable adjustable valves 62 and 63 forcontrolling the amount and pressure of return water to be deliveredthrough the line 61 to the outlet 46 of the trap 22, from the press 28.The line 61 is connected to the trap outlet 46 at 64 either by itself,or optionally with a nozzle 65 at the juncture of the line 61 and trapoutlet 46. Water from the press 28 passing into the trap 22 provides anassist or back flush for the trap 46 to help convey the solids from thetrap 22 to the ejector 48, through a predetermined lateral distance,such as that illustrated in FIG. 2. The use of line 61 permits theconveyance of solids for several feet horizontally and eliminates theneed for a specific position of the trap relative to the ejector.

It will thusbeseen that there is presented an entire system of the typeearlier described.

It will further be noted that there is an additional reason for ventingemulsions and foams formed during the pulping apparatus prior to thepassage of the slurry into the comminution apparatus 24. The apparatus24 also functions as a pump, and emulsions and bubbly foams generallypresent substantial difficulty to pumps and to grinders of the type ofapparatus 24, which thereby renders the use of a vent 34 to be highlydesirable. By so locating the vent, that in addition to solving thisproblem, it is so located that it does not tend to clog with lightstyrene foams and the like, a unique overall arrangement is presented.

Because of the capability of the trap means 22, to act as a pump, itwill be noted that in some instances, as when the pulping apparatus 11is operating at a decreased capacity, it may be desirable to permit thetrap 22 to fill periodically, with intermittant emptying of theaccumulated solids by the use of the ejector 48, rather than continuousoperation of the ejector 48 and commensurate continuous emptying ofsolids from the hopper bottom of the trap 22. I

With reference to FIG. 3 in detail, a line 70 is illusas an optionalback flush arrangement. The line 70 could be provided with water from apress, such as that 28 of FIG. 1, or it could be a fresh water line, ifdesired,

as also could be the line 61 in FIG. I, if desired,

It WIII be apparent that other modifications and variations of theapparatus of this invention, as well as modifications of the use andoperation thereof may all take place, within the spirit and scope of theinvention as defined in the appended claims.

What is claimed is:

1. Apparatus for preparation of waste solids for disposal comprisingmeans for receiving and pulping solids by abrasion in a liquid medium toa predetermined reduced particle size and having a pulp slurry dischargeopening, and trap means having an inlet connected downstream of thedischarge opening of said pulping means for receiving a pulp slurrydischarged therefrom through a trap means inlet, said trap means havinga slurry outlet for discharging a slurry therefrom and being providedwith a solids outlet at the bottom thereof for discharge of heaviersolids received from said pulping means, including means providing aseparate water inlet to said solids outlet of said trap means forassisting removal of solids through said solids outlet.

2. The apparatus of claim 1, including solids ejector means connected atthe solids outlet of said trap means for receiving solid debris in aliquid medium from said trap means and ejecting solid debris thusreceived from the liquid medium.

3. The apparatus of claim 1, wherein said solids outlet and said meansproviding a water inlet comprise means for facilitating lateraldisplacement of solids from said trap means.

4. The apparatus of claim 1, wherein said means providing a water inletcomprises venturi means.

5. The apparatus of claim 1, including a pressing apparatus in thecombination connected to said other comminuting apparatus and adapted toreceive a slurry therefrom and condense solids from the slurry.

6. The apparatus of claim 5, including a water return line connectingsaid pressing apparatus and said pulping apparatus for delivery of waterextracted from condensed solids in said pressing apparatus back to saidpulping apparatus, including valve means for controlling the flow ofwater from said water return line to said water inlet of said solidsoutlet.

4' i t i

1. Apparatus for preparation of waste solids for disposal comprising means for receiving and pulping solids by abrasion in a liquid medium to a predetermined reduced particle size and having a pulp slurry discharge opening, and trap means having an inlet connected downstream of the discharge opening of said pulping means for receiving a pulp slurry discharged therefrom through a trap means inlet, said trap means having a slurry outlet for discharging a slurry therefrom and being provided with a solids outlet at the bottom thereof for discharge of heavier solids received from said pulping means, including means providing a separate water inlet to said solids outlet of said trap means for assisting removal of solids through said solids outlet.
 1. Apparatus for preparation of waste solids for disposal comprising means for receiving and pulping solids by abrasion in a liquid medium to a predetermined reduced particle size and having a pulp slurry discharge opening, and trap means having an inlet connected downstream of the discharge opening of said pulping means for receiving a pulp slurry discharged therefrom through a trap means inlet, said trap means having a slurry outlet for discharging a slurry therefrom and being provided with a solids outlet at the bottom thereof for discharge of heavier solids received from said pulping means, including means providing a separate water inlet to said solids outlet of said trap means for assisting removal of solids through said solids outlet.
 2. The apparatus of claim 1, including solids ejector means connected at the solids outlet of said trap means for receiving solid debris in a liquid medium from said trap means and ejecting solid debris thus received from the liquid medium.
 3. The apparatus of claim 1, wherein said solids outlet and said means providing a water inlet comprise means for facilitating lateral displacement of solids from said trap means.
 4. The apparatus of claim 1, wherein said means providing a water inlet comprises venturi means.
 5. The apparatus of claim 1, including a pressing apparatus in the combination connected to said other comminuting apparatus and adapted to receive a slurry therefrom and condense solids from the slurry. 